You have to collect special shells to use in a shop full of miniature statues. You can't just buy the statues. You have to gamble the special shells. The more shells you put up, the more likely it is to win a statue. Every time you bet on a statue, you have to scroll through a dialog, perform an action, and watch a short animation. It quickly becomes more work than play. The shells aren't used for a darn thing other than obtaining statues.
Furthermore, I don't quite understand the concept of statues as unlockables in video games. I'd rather have new characters, regular art work, usable items, video clips, music, etc. There are little statues to unlock in SSX3, which is odd enough. Unlockable statues on the GBA SP seem like nothing more than teeny, tiny, almost random graphics. Of course, each little statue was accompanied by a hint or tip, but still...
If you ever play this game, either anticipate the little statues and decide to go crazy collecting shells, or decide at the beginning not to worry about them.
Overall, I would totally recommend the game to other Zelda fans.